[Maria-developers] MWL#89 "Cost-based choice between Materialization and IN->EXISTS" rev1 for review

Igor, Please find attached a combined patch for the first implementation of: MWL#89 Cost-based choice between Materialization and IN->EXISTS The tree is in Lanunchpad under buildbot: https://code.launchpad.net/~maria-captains/maria/5.3-mwl89 Timour